Closed account etc

I bought a dress on my account mid-October. Mid-Nov I was told my account has been closed due to inactivity, which I accepted, forgetting the Oct purchase. End of Nov I received an sms re a R45 installment. I immediately sent an email querying this, still forgetting the dress, to which I still haven't received a reply. The next thing I received another sms that I am in arrears, interest of R4,32 has been added and I owe R94,32. On 16 Dec I received a call asking when exactly am I going to pay my account and I promised to pay it the next day but that they have closed my account. Within a minute I received an sms stating that my account will be monitored and that I will be handed over to the Credit Buro if I don't pay. My problem is this - I have no problem being charged interest on paying late, but to hound me for R45!! I have been an account holder for 15 years or more, never having fallen behind. My account was closed without my knowledge and it was an issue when I did drive to Knysna the next day to settle the account to actually pay!! Your admin is in shambles and you have made it abundantly clear that you do not want my business and I am glad you can afford to loose me!